"One would have to suspect that the welfare reforms in 2006 have played a role," he said.

"Those reforms shifted a number of single parents onto the unemployment benefit, the Newstart Allowance, which has a lower rate of benefit and perhaps more importantly has a tougher income test.

"The majority of single parents are employed on at least a part-time basis and so such part-time employment would tend to decrease the benefits more rapidly than on the parenting payment."

The Gillard Government this year made further changes, moving all single parents onto the Newstart Allowance once their youngest child turns eight.

Associate Professor Wilkins says that move will "almost certainly" cause the numbers of children living in poverty to increase again.

"There was some increase in the allowance for earnings on the Newstart benefit for these single parents," he said.

"But on balance one would expect to see a rise in poverty among children in lone-parent households, at least in the short term."

But he says the long-term consequences for children remain to be seen.

"If this policy is promoting employment of single parents, and in the longer term creating greater self-reliance and higher incomes among those households, then it may actually be in the longer term interests of those children," he said.